Don't Leave Me Again
by Lola McCarthy
Summary: One day Isabella gets a strange letter from Phineas. He says he has to leave, and the whole Flynn-Fletcher family goes missing overnight. They've left cryptic clues behind. Will Isabella be able to find and save the family, while managing to stay safe?
1. Chapter 1 Prologue

She picked the letter up with uncertainty. She was scared of what might happen. It had been lying on her nightstand for days. She was afraid of it like it was some infectious disease ready to become an epidemic at any moment. But she was ready, now. Ready to face anything.

It read:

_Why thank you,_

_For the kiss,_

_The kiss that wasn't meant to be._

_For the feelings you had,_

_For the words you spoke,_

_And the thoughts you had of me._

_I'm sorry, my love._

_So sorry for pain._

_Sorry for the things that I did._

_I never deserved your love,_

_Never deserved your devotion._

_But now my pain I must rid._

_You won't be able to find me._

_I leave alone and in silence,_

_But please remember my name._

_I'll be fine._

_Don't worry about me._

_But know that I won't be the same._

_One day I might come out_

_Out of hiding and out of the dark,_

_And visit you._

_But maybe you'll find me._

_I hope you will come._

_But I'll always love you, whatever you do._

_Sorry, Isabella. But I have to leave._

_I love you… _

_~Phineas Edward Flynn_

She felt one, single, lonely teardrop fall into her hands.


	2. Chapter 2 Welcome To My HQ

"Miss Garcia-Shapiro, where were you on July 6th, at around…say, 4:27 P.M.?"

"At home, sir. Yes, I remember now. I was at home eating dinner with my mom. My father was still at work. He had called and said he was going to be late. He works at the Tri-State Area airport." She looked around the room.

"Did you happen to look out of the window at any point during dinner?"

"No, sir." She fiddled with her hair.

"So you saw nothing happening at the Flynn-Fletcher household?"

She let out a gasp. "The Flynn-Fletcher household…" She paused before saying,

"…No sir. I saw nothing happen."

* * *

><p><strong>2 Weeks earlier…<strong>

Isabella casted a sideways glance at Perry. The blue-green mammal was just walking in at a random moment, as Phineas said, as if on cue,

"Oh! There you are, Perry." He grinned at his pet. "Where do you disappear to everyday?" But his question was only replied with a contented,

"Grrrrrrr…" Perry looked up as a certain girl with long black hair entered the Flynn-Fletcher backyard.

"Hi, Phineas! Whatcha doing?"

"Oh…hi, Isabella. We're just figuring out blueprints for a flying monkey robot." Phineas smiled.

"It's gonna be awesome! See, I've heard rumors…" he looked around and took Isabella aside. "I've heard rumors that there is a secret agency, OWCA, which trains animals to be secret agents. And…I thought maybe it would be cool to find out if Perry is an agent or not. So, Ferb and I decided to make a flying robot monkey, because monkeys are smart. And it's an animal. And it's a robot, so it can go almost anywhere." He said this in one breath.

"Wow. And…Why does it fly?" She cocked her head.

"Oh. 'Cause flying is cool." He shrugged and turned back to work.

"I just need to figure out a super cool feature that might be able to scan for hidden entrances. You can help, too," he said.

Isabella replied, "Um…Phineas? I don't think that-"

"Okay…here are the blueprints so far. Baljeet'll be here in a few minutes to help with the mechanics part of it. I need you to add some designs for a scanner."

"But Phineas-" she started to say, but was interrupted again.

"Hey-where's Ferb?" Phineas scratched his head. "Oh, well. Ferb is Ferb."

Isabella grabbed the blueprints reluctantly and huffily sat down to work on the designs. Perry walked up and curled next to Isabella on the grass.

"Grrrrrr…" He said.

"I know, Perry. But there's nothing I can do!" she whispered.

"Grrrrrr…"

"Agent P, I can't say no to Phineas."

"Grrrrrrrrr…" This time the chattering was louder. He pulled back his fur on his wrist, revealing a certain, small watch, with certain, talking image that had a large nose, a white mustache, and gray hair.

"Whoa, Agent P!" The image said.

Isabella rolled her eyes. "I'll tell him _later_!"

Her remark was once again met with a "Grrrrrr…" but was more of a mutter as Perry strolled away.

**~later on~**

Later, that night, in her room, Isabella looked at Pinky. "Ready?" She asked.

Pinky nodded.

Isabella walked up to her wall and pressed a hidden button. A screen appeared with Major Monogram and Agent P.

"Hello, Agent Pinky, hello Isabella," MM said.

"Hello, Grandfather, Agent P. Welcome to my HQ."


	3. Chapter 3 The Inator

"Miss Isabella Garcia-Shapiro to the stand."

She walked nervously up to the witness stand.

"Do you swear to tell the truth, the whole truth, and nothing but the truth, so help you, God?"

"I do swear to tell the truth, the whole truth, and nothing but the truth, so help me God."

The defendant's lawyer stood up.

"Miss Garcia-Shapiro, where were you on July 6th, at around…say, 4:27 P.M.?"

"At home, sir. Yes, I remember now. I was at home eating dinner with my mom. My father was still at work. He had called and said he was going to be late. He works at the Tri-State Area airport." She looked around the room.

"Did you happen to look out of the window at any point during dinner?"

"No, sir." She fiddled with her hair.

"So you saw nothing happening at the Flynn-Fletcher household?"

She let out a gasp. "The Flynn-Fletcher household…" She paused before saying,

"…No sir. I saw nothing happen."

"Miss Garcia-Shapiro, how old are you?"

"I'm 13, sir."

"I see. Who else was at dinner with you?"

"My grandfather, sir." She absent-mindedly scratched her ear.

"And who is your grandfather?"

"Major Francis Hughe Monogram."

* * *

><p><strong>2 Weeks Earlier…<strong>

"Welcome to my HQ." She zoomed the camera out so MM and Perry could see the room.

Agent P was wearing some sort of modified Perry-translator much like the one Phineas and Ferb had built earlier in the summer. This one, however, was portable, and actually worked on Perry, as well as other animals. Pinky was also wearing the same thing, so the two animals and two humans could talk normally in English.

"Yes, Isabella's home is very comfy. I would be going to sleep right now except Izzy here delayed the meeting." Pinky was shaking and was talking in a slight Spanish accent.

"I tried to get her to come right then, but noooooo, she couldn't say no to her boyfriend." Perry rolled his eyes, annoyed.

"Humans are so annoying sometimes!" Pinky said.

"I know, right! You can never get them to do what you want." Perry shook his head.

"Isn't that the truth! You know, one time, I was at the park and Isa-"

"Okay, you guys!" Isabella said. "We're not here to discuss the irritating personality traits of humans."

"Right. Agent P, fill them in," Major Monogram said.

"Okay. Apparently Dr. D has devised a plan to make certain things disappear. And it includes a certain -inator that stimulates creativity in the minds of young ones."

"Isn't that a good thing?" Isabella asked.

"Well, normally, yes. But for one thing, this is Doofenshmirtz we're talking about. And, for another…"MM trailed off.

"As we all well know, Doof has been out to destroy OWCA and our agents since I can remember. And there is no way that his plan is going to involve something that is not out to destroy humanity, beauty, OWCA, or our agents," Perry continued.

"Here's where I come in with my bit of information," Isabella said. "I had no idea how useful this was until now…"

"That was exactly why I needed you to come right then," Perry muttered under his breath.

"See, my mom and I were at the mall the other day. And I thought I spotted Doofenshmirtz. He was buying some sort of mechanical arm robot type thing that paints. I just didn't know how valuable that was until just a second ago."

"That would explain it," Pinky said. "I've been doing some research and I have found that Doofenshmirtz's –inator involves things such as drawing, painting, and writing. As well as curiosity."

"All the things children need to be creative. Unfortunately, Doof's plan involves more than just a creativity –inator. This –inator is designed so that whenever it hits its target, it will make them get too curious. He's already hit several test people; mostly kids. They all have something in common. They all have pets. Now, these pets are not agents, but, from the information we gathered, Doof is planning to zap children with this –inator, besides the test subjects. And they're all ones with pets. Not just any pets, however. These are OWCA secret agent pets." MM looked the other three in the eye. "If and when the -inator strikes these innocent children, the curiosity beams formed in the rays of the inator will cause them to want to find out where their pet disappears to every day. Hence me mentioning the importance of Doofenshmirtz wanting to get rid of OWCA."

Perry spoke up next. "Isabella," he said. "If Phineas and Ferb get hit with the –inator, there is a good chance they'll find out I'm a secret agent. If they find out I'm a secret agent, the whole family has to go away and we won't ever be able to see them again. We can't have that. And I don't want to have to use the amnesia-inator on them like last time they found out I was an agent. Which is why this mission is especially important to me."

Isabella was wearing a somewhat shocked expression on her face.

"What's wrong?" The other three asked in unison.

"I-I think they've already gotten zapped."


End file.
